drivers/i2c/busses/i2c-iop3xx.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* ------------------------------------------------------------------------- */
   3 /* i2c-iop3xx.c i2c driver algorithms for Intel XScale IOP3xx & IXP46x       */
   4 /* ------------------------------------------------------------------------- */
   5 /* Copyright (C) 2003 Peter Milne, D-TACQ Solutions Ltd
   6  *                    <Peter dot Milne at D hyphen TACQ dot com>
   7  *
   8  * With acknowledgements to i2c-algo-ibm_ocp.c by
   9  * Ian DaSilva, MontaVista Software, Inc. idasilva@mvista.com
  10  *
  11  * And i2c-algo-pcf.c, which was created by Simon G. Vogl and Hans Berglund:
  12  *
  13  * Copyright (C) 1995-1997 Simon G. Vogl, 1998-2000 Hans Berglund
  14  *
  15  * And which acknowledged Kyösti Mälkki <kmalkki@cc.hut.fi>,
  16  * Frodo Looijaard <frodol@dds.nl>, Martin Bailey<mbailey@littlefeet-inc.com>
  17  *
  18  * Major cleanup by Deepak Saxena <dsaxena@plexity.net>, 01/2005:
  19  *
  20  * - Use driver model to pass per-chip info instead of hardcoding and #ifdefs
  21  * - Use ioremap/__raw_readl/__raw_writel instead of direct dereference
  22  * - Make it work with IXP46x chips
  23  * - Cleanup function names, coding style, etc
  24  *
  25  * - writing to local target address causes latchup on iop331.
  26  *      fix: driver refuses to address self.
  27  */
  28
  29 #include <linux/interrupt.h>
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/delay.h>
  33 #include <linux/slab.h>
  34 #include <linux/errno.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/i2c.h>
  37 #include <linux/io.h>
  38 #include <linux/gpio/consumer.h>
  39
  40 #include "i2c-iop3xx.h"
  41
  42 /* global unit counter */
  43 static int i2c_id;
  44
  45 static inline unsigned char
  46 iic_cook_addr(struct i2c_msg *msg)
  47 {
  48         unsigned char addr;
  49
  50         addr = i2c_8bit_addr_from_msg(msg);
  51
  52         return addr;
  53 }
  54
  55 static void
  56 iop3xx_i2c_reset(struct i2c_algo_iop3xx_data *iop3xx_adap)
  57 {
  58         /* Follows devman 9.3 */
  59         __raw_writel(IOP3XX_ICR_UNIT_RESET, iop3xx_adap->ioaddr + CR_OFFSET);
  60         __raw_writel(IOP3XX_ISR_CLEARBITS, iop3xx_adap->ioaddr + SR_OFFSET);
  61         __raw_writel(0, iop3xx_adap->ioaddr + CR_OFFSET);
  62 }
  63
  64 static void
  65 iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap)
  66 {
  67         u32 cr = IOP3XX_ICR_GCD | IOP3XX_ICR_SCLEN | IOP3XX_ICR_UE;
  68
  69         /*
  70          * Every time unit enable is asserted, GPOD needs to be cleared
  71          * on IOP3XX to avoid data corruption on the bus. We use the
  72          * gpiod_set_raw_value() to make sure the 0 hits the hardware
  73          * GPOD register. These descriptors are only passed along to
  74          * the device if this is necessary.
  75          */
  76         if (iop3xx_adap->gpio_scl)
  77                 gpiod_set_raw_value(iop3xx_adap->gpio_scl, 0);
  78         if (iop3xx_adap->gpio_sda)
  79                 gpiod_set_raw_value(iop3xx_adap->gpio_sda, 0);
  80
  81         /* NB SR bits not same position as CR IE bits :-( */
  82         iop3xx_adap->SR_enabled =
  83                 IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
  84                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_TXEMPTY;
  85
  86         cr |= IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
  87                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE;
  88
  89         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
  90 }
  91
  92 static void
  93 iop3xx_i2c_transaction_cleanup(struct i2c_algo_iop3xx_data *iop3xx_adap)
  94 {
  95         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
  96
  97         cr &= ~(IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE |
  98                 IOP3XX_ICR_MSTOP | IOP3XX_ICR_SCLEN);
  99
 100         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 101 }
 102
 103 /*
 104  * NB: the handler has to clear the source of the interrupt!
 105  * Then it passes the SR flags of interest to BH via adap data
 106  */
 107 static irqreturn_t
 108 iop3xx_i2c_irq_handler(int this_irq, void *dev_id)
 109 {
 110         struct i2c_algo_iop3xx_data *iop3xx_adap = dev_id;
 111         u32 sr = __raw_readl(iop3xx_adap->ioaddr + SR_OFFSET);
 112
 113         if ((sr &= iop3xx_adap->SR_enabled)) {
 114                 __raw_writel(sr, iop3xx_adap->ioaddr + SR_OFFSET);
 115                 iop3xx_adap->SR_received |= sr;
 116                 wake_up_interruptible(&iop3xx_adap->waitq);
 117         }
 118         return IRQ_HANDLED;
 119 }
 120
 121 /* check all error conditions, clear them , report most important */
 122 static int
 123 iop3xx_i2c_error(u32 sr)
 124 {
 125         int rc = 0;
 126
 127         if ((sr & IOP3XX_ISR_BERRD)) {
 128                 if (!rc)
 129                         rc = -I2C_ERR_BERR;
 130         }
 131         if ((sr & IOP3XX_ISR_ALD)) {
 132                 if (!rc)
 133                         rc = -I2C_ERR_ALD;
 134         }
 135         return rc;
 136 }
 137
 138 static inline u32
 139 iop3xx_i2c_get_srstat(struct i2c_algo_iop3xx_data *iop3xx_adap)
 140 {
 141         unsigned long flags;
 142         u32 sr;
 143
 144         spin_lock_irqsave(&iop3xx_adap->lock, flags);
 145         sr = iop3xx_adap->SR_received;
 146         iop3xx_adap->SR_received = 0;
 147         spin_unlock_irqrestore(&iop3xx_adap->lock, flags);
 148
 149         return sr;
 150 }
 151
 152 /*
 153  * sleep until interrupted, then recover and analyse the SR
 154  * saved by handler
 155  */
 156 typedef int (*compare_func)(unsigned test, unsigned mask);
 157 /* returns 1 on correct comparison */
 158
 159 static int
 160 iop3xx_i2c_wait_event(struct i2c_algo_iop3xx_data *iop3xx_adap,
 161                           unsigned flags, unsigned *status,
 162                           compare_func compare)
 163 {
 164         unsigned sr = 0;
 165         int interrupted;
 166         int done;
 167         int rc = 0;
 168
 169         do {
 170                 interrupted = wait_event_interruptible_timeout (
 171                         iop3xx_adap->waitq,
 172                         (done = compare(sr = iop3xx_i2c_get_srstat(iop3xx_adap), flags)),
 173                         1 * HZ
 174                         );
 175                 if ((rc = iop3xx_i2c_error(sr)) < 0) {
 176                         *status = sr;
 177                         return rc;
 178                 } else if (!interrupted) {
 179                         *status = sr;
 180                         return -ETIMEDOUT;
 181                 }
 182         } while (!done);
 183
 184         *status = sr;
 185
 186         return 0;
 187 }
 188
 189 /*
 190  * Concrete compare_funcs
 191  */
 192 static int
 193 all_bits_clear(unsigned test, unsigned mask)
 194 {
 195         return (test & mask) == 0;
 196 }
 197
 198 static int
 199 any_bits_set(unsigned test, unsigned mask)
 200 {
 201         return (test & mask) != 0;
 202 }
 203
 204 static int
 205 iop3xx_i2c_wait_tx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 206 {
 207         return iop3xx_i2c_wait_event(
 208                 iop3xx_adap,
 209                 IOP3XX_ISR_TXEMPTY | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 210                 status, any_bits_set);
 211 }
 212
 213 static int
 214 iop3xx_i2c_wait_rx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 215 {
 216         return iop3xx_i2c_wait_event(
 217                 iop3xx_adap,
 218                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 219                 status, any_bits_set);
 220 }
 221
 222 static int
 223 iop3xx_i2c_wait_idle(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 224 {
 225         return iop3xx_i2c_wait_event(
 226                 iop3xx_adap, IOP3XX_ISR_UNITBUSY, status, all_bits_clear);
 227 }
 228
 229 static int
 230 iop3xx_i2c_send_target_addr(struct i2c_algo_iop3xx_data *iop3xx_adap,
 231                                 struct i2c_msg *msg)
 232 {
 233         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 234         int status;
 235         int rc;
 236
 237         /* avoid writing to local target address (hangs on 80331),
 238          * forbidden in Intel developer manual
 239          */
 240         if (msg->addr == MYSAR) {
 241                 return -EBUSY;
 242         }
 243
 244         __raw_writel(iic_cook_addr(msg), iop3xx_adap->ioaddr + DBR_OFFSET);
 245
 246         cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 247         cr |= IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE;
 248
 249         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 250         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 251
 252         return rc;
 253 }
 254
 255 static int
 256 iop3xx_i2c_write_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char byte,
 257                                 int stop)
 258 {
 259         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 260         int status;
 261         int rc = 0;
 262
 263         __raw_writel(byte, iop3xx_adap->ioaddr + DBR_OFFSET);
 264         cr &= ~IOP3XX_ICR_MSTART;
 265         if (stop) {
 266                 cr |= IOP3XX_ICR_MSTOP;
 267         } else {
 268                 cr &= ~IOP3XX_ICR_MSTOP;
 269         }
 270         cr |= IOP3XX_ICR_TBYTE;
 271         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 272         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 273
 274         return rc;
 275 }
 276
 277 static int
 278 iop3xx_i2c_read_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char *byte,
 279                                 int stop)
 280 {
 281         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 282         int status;
 283         int rc = 0;
 284
 285         cr &= ~IOP3XX_ICR_MSTART;
 286
 287         if (stop) {
 288                 cr |= IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK;
 289         } else {
 290                 cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 291         }
 292         cr |= IOP3XX_ICR_TBYTE;
 293         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 294
 295         rc = iop3xx_i2c_wait_rx_done(iop3xx_adap, &status);
 296
 297         *byte = __raw_readl(iop3xx_adap->ioaddr + DBR_OFFSET);
 298
 299         return rc;
 300 }
 301
 302 static int
 303 iop3xx_i2c_writebytes(struct i2c_adapter *i2c_adap, const char *buf, int count)
 304 {
 305         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 306         int ii;
 307         int rc = 0;
 308
 309         for (ii = 0; rc == 0 && ii != count; ++ii)
 310                 rc = iop3xx_i2c_write_byte(iop3xx_adap, buf[ii], ii == count-1);
 311         return rc;
 312 }
 313
 314 static int
 315 iop3xx_i2c_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count)
 316 {
 317         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 318         int ii;
 319         int rc = 0;
 320
 321         for (ii = 0; rc == 0 && ii != count; ++ii)
 322                 rc = iop3xx_i2c_read_byte(iop3xx_adap, &buf[ii], ii == count-1);
 323
 324         return rc;
 325 }
 326
 327 /*
 328  * Description:  This function implements combined transactions.  Combined
 329  * transactions consist of combinations of reading and writing blocks of data.
 330  * FROM THE SAME ADDRESS
 331  * Each transfer (i.e. a read or a write) is separated by a repeated start
 332  * condition.
 333  */
 334 static int
 335 iop3xx_i2c_handle_msg(struct i2c_adapter *i2c_adap, struct i2c_msg *pmsg)
 336 {
 337         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 338         int rc;
 339
 340         rc = iop3xx_i2c_send_target_addr(iop3xx_adap, pmsg);
 341         if (rc < 0) {
 342                 return rc;
 343         }
 344
 345         if ((pmsg->flags&I2C_M_RD)) {
 346                 return iop3xx_i2c_readbytes(i2c_adap, pmsg->buf, pmsg->len);
 347         } else {
 348                 return iop3xx_i2c_writebytes(i2c_adap, pmsg->buf, pmsg->len);
 349         }
 350 }
 351
 352 static int
 353 iop3xx_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
 354                 int num)
 355 {
 356         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 357         int im = 0;
 358         int ret = 0;
 359         int status;
 360
 361         iop3xx_i2c_wait_idle(iop3xx_adap, &status);
 362         iop3xx_i2c_reset(iop3xx_adap);
 363         iop3xx_i2c_enable(iop3xx_adap);
 364
 365         for (im = 0; ret == 0 && im != num; im++) {
 366                 ret = iop3xx_i2c_handle_msg(i2c_adap, &msgs[im]);
 367         }
 368
 369         iop3xx_i2c_transaction_cleanup(iop3xx_adap);
 370
 371         if (ret)
 372                 return ret;
 373
 374         return im;
 375 }
 376
 377 static u32
 378 iop3xx_i2c_func(struct i2c_adapter *adap)
 379 {
 380         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 381 }
 382
 383 static const struct i2c_algorithm iop3xx_i2c_algo = {
 384         .xfer = iop3xx_i2c_xfer,
 385         .functionality = iop3xx_i2c_func,
 386 };
 387
 388 static void
 389 iop3xx_i2c_remove(struct platform_device *pdev)
 390 {
 391         struct i2c_adapter *padapter = platform_get_drvdata(pdev);
 392         struct i2c_algo_iop3xx_data *adapter_data =
 393                 (struct i2c_algo_iop3xx_data *)padapter->algo_data;
 394         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 395         unsigned long cr = __raw_readl(adapter_data->ioaddr + CR_OFFSET);
 396
 397         /*
 398          * Disable the actual HW unit
 399          */
 400         cr &= ~(IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
 401                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
 402         __raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
 403
 404         iounmap(adapter_data->ioaddr);
 405         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 406         kfree(adapter_data);
 407         kfree(padapter);
 408 }
 409
 410 static int
 411 iop3xx_i2c_probe(struct platform_device *pdev)
 412 {
 413         struct resource *res;
 414         int ret, irq;
 415         struct i2c_adapter *new_adapter;
 416         struct i2c_algo_iop3xx_data *adapter_data;
 417
 418         new_adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 419         if (!new_adapter) {
 420                 ret = -ENOMEM;
 421                 goto out;
 422         }
 423
 424         adapter_data = kzalloc(sizeof(struct i2c_algo_iop3xx_data), GFP_KERNEL);
 425         if (!adapter_data) {
 426                 ret = -ENOMEM;
 427                 goto free_adapter;
 428         }
 429
 430         adapter_data->gpio_scl = devm_gpiod_get_optional(&pdev->dev,
 431                                                          "scl",
 432                                                          GPIOD_ASIS);
 433         if (IS_ERR(adapter_data->gpio_scl)) {
 434                 ret = PTR_ERR(adapter_data->gpio_scl);
 435                 goto free_both;
 436         }
 437         adapter_data->gpio_sda = devm_gpiod_get_optional(&pdev->dev,
 438                                                          "sda",
 439                                                          GPIOD_ASIS);
 440         if (IS_ERR(adapter_data->gpio_sda)) {
 441                 ret = PTR_ERR(adapter_data->gpio_sda);
 442                 goto free_both;
 443         }
 444
 445         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 446         if (!res) {
 447                 ret = -ENODEV;
 448                 goto free_both;
 449         }
 450
 451         if (!request_mem_region(res->start, IOP3XX_I2C_IO_SIZE, pdev->name)) {
 452                 ret = -EBUSY;
 453                 goto free_both;
 454         }
 455
 456         /* set the adapter enumeration # */
 457         adapter_data->id = i2c_id++;
 458
 459         adapter_data->ioaddr = ioremap(res->start, IOP3XX_I2C_IO_SIZE);
 460         if (!adapter_data->ioaddr) {
 461                 ret = -ENOMEM;
 462                 goto release_region;
 463         }
 464
 465         irq = platform_get_irq(pdev, 0);
 466         if (irq < 0) {
 467                 ret = irq;
 468                 goto unmap;
 469         }
 470         ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
 471                                 pdev->name, adapter_data);
 472
 473         if (ret)
 474                 goto unmap;
 475
 476         memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
 477         new_adapter->owner = THIS_MODULE;
 478         new_adapter->class = I2C_CLASS_HWMON;
 479         new_adapter->dev.parent = &pdev->dev;
 480         new_adapter->dev.of_node = pdev->dev.of_node;
 481         new_adapter->nr = pdev->id;
 482
 483         /*
 484          * Default values...should these come in from board code?
 485          */
 486         new_adapter->timeout = HZ;
 487         new_adapter->algo = &iop3xx_i2c_algo;
 488
 489         init_waitqueue_head(&adapter_data->waitq);
 490         spin_lock_init(&adapter_data->lock);
 491
 492         iop3xx_i2c_reset(adapter_data);
 493         iop3xx_i2c_enable(adapter_data);
 494
 495         platform_set_drvdata(pdev, new_adapter);
 496         new_adapter->algo_data = adapter_data;
 497
 498         i2c_add_numbered_adapter(new_adapter);
 499
 500         return 0;
 501
 502 unmap:
 503         iounmap(adapter_data->ioaddr);
 504
 505 release_region:
 506         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 507
 508 free_both:
 509         kfree(adapter_data);
 510
 511 free_adapter:
 512         kfree(new_adapter);
 513
 514 out:
 515         return ret;
 516 }
 517
 518 static const struct of_device_id i2c_iop3xx_match[] = {
 519         { .compatible = "intel,iop3xx-i2c", },
 520         { .compatible = "intel,ixp4xx-i2c", },
 521         {},
 522 };
 523 MODULE_DEVICE_TABLE(of, i2c_iop3xx_match);
 524
 525 static struct platform_driver iop3xx_i2c_driver = {
 526         .probe          = iop3xx_i2c_probe,
 527         .remove         = iop3xx_i2c_remove,
 528         .driver         = {
 529                 .name   = "IOP3xx-I2C",
 530                 .of_match_table = i2c_iop3xx_match,
 531         },
 532 };
 533
 534 module_platform_driver(iop3xx_i2c_driver);
 535
 536 MODULE_AUTHOR("D-TACQ Solutions Ltd <www.d-tacq.com>");
 537 MODULE_DESCRIPTION("IOP3xx iic algorithm and driver");
 538 MODULE_LICENSE("GPL");
 539 MODULE_ALIAS("platform:IOP3xx-I2C");